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Green River Watershed

The Green River begins in the Cascade Mountains near Stampede Pass and serves as Tacoma Water’s primary water supply.

For more than 90 years, Tacoma Water has managed the Green River watershed. This forested land serves as a collecting point for melting snow and seasonal rainfall. The watershed covers 147,394 acres on the west flank of the Cascade Mountains between Chinook and Snoqualmie passes. Tacoma Water owns only 10% of the watershed, but has agreements with other landowners to limit activities in order to keep the Green River water supply pure and fresh.

The Green River is also the source of water for a regional partnership formed by the City of Kent, the Covington Water District, the Lakehaven Utility District and Tacoma Water. The Regional Water Supply System (RWSS) supplies up to 65 million gallons per day (MGD) to Tacoma Water and its project partners.

We also operate a wellfield along the North Fork of the Green River within the watershed. The North Fork wells are used to meet Tacoma’s needs when the water in the river is too turbid (or cloudy), usually in the fall and winter, or in the event of other unusual or unacceptable water quality in the Green River.


Protecting Our Watershed

The Green River watershed is surrounded by mountains on three sides; gates and guards limit public access to minimize contamination. We take samples of water at our intake where we divert water into transmission pipelines that bring water into the city. We also take weekly samples from tributary streams throughout the watershed that feed the Green River to help anticipate problems before they reach our intake.


Green River Watershed Management Plan

The Green River Watershed Management Plan and Wellhead Protection Program help Tacoma Water aggressively protect our community’s water supply and enables the utility to provide more than 300,000 customers with safe and reliable water.